diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
index 90ef61d449d..c7a3ab0b05d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
@@ -941,6 +941,11 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                 return super.toDefaultValue(schema);
             }
             return null;
+        } else if (ModelUtils.isComposedSchema(schema)) {
+            if (schema.getDefault() != null) {
+                return super.toDefaultValue(schema);
+            }
+            return null;
         }
 
         return super.toDefaultValue(schema);
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Drawing.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Drawing.java
index ccae4aaacd6..b985283f698 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Drawing.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Drawing.java
@@ -53,13 +53,13 @@ import org.openapitools.client.JSON;
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class Drawing {
   public static final String JSON_PROPERTY_MAIN_SHAPE = "mainShape";
-  private Shape mainShape = null;
+  private Shape mainShape;
 
   public static final String JSON_PROPERTY_SHAPE_OR_NULL = "shapeOrNull";
-  private ShapeOrNull shapeOrNull = null;
+  private ShapeOrNull shapeOrNull;
 
   public static final String JSON_PROPERTY_NULLABLE_SHAPE = "nullableShape";
-  private JsonNullable<NullableShape> nullableShape = JsonNullable.<NullableShape>of(null);
+  private JsonNullable<NullableShape> nullableShape = JsonNullable.<NullableShape>undefined();
 
   public static final String JSON_PROPERTY_SHAPES = "shapes";
   private List<Shape> shapes = null;
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java
index de331b2bd2c..7700a65f0a5 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java
@@ -54,13 +54,13 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 @javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class Drawing extends HashMap<String, Fruit> {
   public static final String JSON_PROPERTY_MAIN_SHAPE = "mainShape";
-  private Shape mainShape = null;
+  private Shape mainShape;
 
   public static final String JSON_PROPERTY_SHAPE_OR_NULL = "shapeOrNull";
-  private ShapeOrNull shapeOrNull = null;
+  private ShapeOrNull shapeOrNull;
 
   public static final String JSON_PROPERTY_NULLABLE_SHAPE = "nullableShape";
-  private JsonNullable<NullableShape> nullableShape = JsonNullable.<NullableShape>of(null);
+  private JsonNullable<NullableShape> nullableShape = JsonNullable.<NullableShape>undefined();
 
   public static final String JSON_PROPERTY_SHAPES = "shapes";
   private List<Shape> shapes = null;